Solve for $x$ and $y$ using substitution. ${4x-3y = -1}$ ${x = 3y-7}$
Explanation: Since $x$ has already been solved for, substitute $3y-7$ for $x$ in the first equation. ${4}{(3y-7)}{- 3y = -1}$ Simplify and solve for $y$ $12y-28 - 3y = -1$ $9y-28 = -1$ $9y-28{+28} = -1{+28}$ $9y = 27$ $\dfrac{9y}{{9}} = \dfrac{27}{{9}}$ ${y = 3}$ Now that you know ${y = 3}$ , plug it back into $\thinspace {x = 3y-7}\thinspace$ to find $x$ ${x = 3}{(3)}{ - 7}$ $x = 9 - 7$ ${x = 2}$ You can also plug ${y = 3}$ into $\thinspace {4x-3y = -1}\thinspace$ and get the same answer for $x$ : ${4x - 3}{(3)}{= -1}$ ${x = 2}$